I have never been able to figure out the mechanics of how to consistently upgraded my roads from the basic road. I do get the option to upgraded my roads from time to time but never on a consistent basis. I can often build a road and, when completed, I don't have the option to upgrade. I move the settler off and back and still do not get the option. Yes, I have enough gold to pay for the upgrade. What is the mechanic I am missing? Can I only upgrade on a certain terrain type? Only a certain type of Settler can upgrade? Do they all need to be connected or something? If anyone can help that would be great.